HIGH 8.8 NVD
CVE-2026-86099
Chainlit through 2.12.0 fails to validate the client-supplied socket.io sessionId parameter, allowing unauthenticated attackers to traverse filesystem paths by
Chainlit through 2.12.0 fails to validate the client-supplied socket.io sessionId parameter, allowing unauthenticated attackers to traverse filesystem paths by injecting absolute or relative path sequences. Attackers can craft malicious sessionId values that escape the upload directory and recursively delete arbitrary directories accessible to the service process.
References
- https://github.com/Chainlit/chainlit
- https://github.com/Chainlit/chainlit/blob/2.12.0/backend/chainlit/session.py
- https://github.com/Chainlit/chainlit/blob/2.12.0/backend/chainlit/socket.py
- https://pypi.org/project/chainlit/
- https://www.vulncheck.com/advisories/chainlit-through-2.12.0-path-traversal-via-socket-io-
This high severity vulnerability with a CVSS score of 8.8 was published on 2026-09-09 via NVD.
vulnfeed aggregates 13138 vulnerabilities from NVD, CISA KEV,
Ubuntu, Debian, Red Hat, Kubernetes, Exploit-DB, OSS-Security, GitHub and OpenStack — updated every 4 hours.